Treatment of residual liquor



wRaymondiG. Booty, Granville, Ohio, assignor, by mesne to use or torecover its major constituent of resin as 35 2,851,433 Patented Sept. 9,1958 United States Patent-Ofitice the mass at .75 C. After anaddtitional 40 minutes the mass siscooled to 60 C.

Then '250 pounds ofanhydrous disodium phosphate Na HPQ is addedand,'when it is dissolved, the cooling 5 is continued to 30 C. Then 350pounds of a 75% solution-in .waterxof phosphoric .acid H PO is added,which p brings thepH to 7.6 and raises the temperature to onelil-iacorpomtlon of 111111015 in the range from 34.to 40 C. On standing,two Application March 1955 liquid layers form with aqueous phosphatesolution in ;493,574 l0 tjl lhelclawer lzltyer and a Icllgwatered resinsolutilon above. e. ower ayer .is wit rawn as a typical i nor for 20Clalmspracticeofthe present invention. Modification s of the procedureare disclosed in my copending application Serial .No. 367,496, filed:July 13, 1953, now abandoned, The Present lilventlon relates to thetreatment of .andin my copending application Serial No. 500,057, filedresidual process liquor for the recovery of useful ingredi- A il 8,1955, as a continuation-in-part of aid Serial ents thereof. Inparticular, it relates to the .treat- No. 367,496. ment Of an aqueoussalt solution containing residual ortypical analysis of the loweraqueous phase result. ganic material deriving from an alkalinecondensation i fromflw process b d ib d i as f ll TREATMENT OF RESIDUALLIQUOR assignments, to American-Marietta Company, Chicago,

reaction between phenol and formaldehyde.

It is known to condense phenol and formaldehyde in Mlxd 3 23 Percent anaqueous mass in the presence of an alkaline catalyst NBQHTO to form aso-called water-soluble phenol-formaldehyde N YH re in, conventionally,the formed solution of said resin formaldehyde vis dewatered by vacuumevaporation. However, it is 25 P1161191 "7" possible to dewater such acondensation mass by the ggjg addition of saline material to salt outthe resin as a liquid layer in aphase-forming action. As aresult, salineDepending upon numerous factors, such as the permaterial is Con entrat din the lower q o Phase and .fection in phase iseparation, and the extentof the resinthe resin substance is concentrated in the -.upper liquid.forminglreaction, the resin content may be present in phase, Withdistribution of small amounts of saline mapart as a suspension and inpart as a solute, By centerial and Water in the resin Phase and smallamounts of trifugal separation the suspended resin may be recovered,organic substance in the aqueous phase. Upon sepayielding a saltsolutionfor practice of the present inration of the two phases, the resin phasemay be processed ti Such a solution has presented problems in economy tosecure the salt content in reusableform, and to secure dissolvedresin'for use, preferably as an addition to matesodillm saltofOrthophosphorisacid, and Predominantly rial made by a process which alsoproduces the salt solui i m o h p p the q phase y tion tobe treated. Ihave discovered that the dissolved tain from 25% to 01' m r f u salinesllh- 40 resin .content in the solution may be advanced to the Stance,commonly about and p to approximately extent that there is formed insaid solution a distinct 6% of dissolved organic.constituents,.including resin in liquid, gel or solid phase containingthe resin which an amount of about 2% of-the whole. The constitutionphase maybe. separated from the salt-containing phase of such a liquorPresents Problems in treating it to to recover the resin. If. the resincontent is appreciable, COVeI a Content eCOIlOmicallY as a useful saltmaterial 4.5 itiis preferred'to separate it as a liquid for usefulrecovery free from organic contaminants, and to recover the resin f it,Ho v mall or ven useful amounts may be content. retained as a liquiduntil such time as it gels or solidifies It is an object of the pr s ntnv i t p o i a inthe heating step. By heating the salt solution at amethod for treating such a salt solution to recover intemperature in therange from 70 C. to its boiling temgredients thereof for economicutility. 5O perature of about 105' C., at atmospheric pressure, the Itis a parti ular j t f the invention to Provide a resin-phase formationtakes place. This occurs in the method for recovering a useful saltproduct substantially first few minutes at the boiling point, but at 90C. free from organic contaminants. about one'hour is needed and a stilllonger time as the It is also an-object of the invention to separate ttemperature'islower. Temperatures above 105 C. and organic and inorganicsolutes of su h quor and t ,pressures'aboveatmospheric may be used tofurther acprovide one or more useful materials. 'celeratethe reactionsbut this is not preferred for obvi- Various other and ancillary objectsandadvantages of ous reasons. the invention will become apparent fromthe following ""When the heating is continued after the liquid-resindescription and explanation of the inventionphase is formedand-separated, for a total time of several In order to illustrate onemanner in which the salt days at 70 'C. or about '12 hours at 90 C. tothe solution for the present inv ntion may h p od ce One atmosphericboiling temperature, a granular phenolic preexample is g but it is to beunderstood that the cipitate is formed which includes all the phenol ofthe invention is not limited to any particular process for originalliquor and the phenol-alcohols, all as phenolyielding the mixed solutionto be treated by the present alcohols, leaving in solution only the saltand residual invention. formaldehyde. If the resin content has beenretained, U. S. P. phenol in the amount of 3140 pounds is it'maybe'contaminated with this precipitate on separamixed with 5500 pounds ofaqueous formaldehyde solu- -tion. tion containing 50% by weight offormaldehyde HCHO, The pH'of the liquid for the above-described heatingless than 2% of methyl alcohol and the remainder Water. operation-may befrom 5 to 9, but it preferably is main- To the mixture at 75 C. isslowly added 450 pounds of a tained at pH of 7. The extent to which thephenol- 50% by weight solution of caustic soda NaOH in water,"formaldehyde condensation mass is neutralized at the at a regular ratewithin 60 minutes, while maintaining time of salting out for phaseformation predeterrnines well as its minor constituents of salinematerial.

When the saline material of the two-phase mass is a However, such pH mayis no resulting contamination of the desired end-product salt.

When the pH at the time of heating for the desired separation is over 9,the formaldehyde content is converted by a prolonged reaction to arelatively non-volatile substance, and, therefore, not subject toremoval by the process. Such solid material forms a contaminant of theend-product salt. If the pH of the mass being heated is under 5, theprecipitate of phenol-alcohols is not formed. When a higher pH range inthe dried salt is desired, it is necessary to add the caustic soda afterseparating the resin and polyphenols, but just before drying to avoidconverting the formaldehyde to a non-volatile form.

Thus, in processing the liquor, the resin-containing phase is formed,and removed as a liquid or retained, and then the precipitated phase isformed. When the liquid resin phase is retained, it later gels and thensolidifies.

As a gel or solid it may remain in the vessel and parted from theaqueous phase at any time, as in isolating the latter after theprecipitation is completed. A clear salt solution may be recovered byfiltration or decantation. The resulting salt solution may be treated toevaporate the water and form a solid salt, with loss of formaldehyde inthe process. This is preferably done by passing the solution over a drumdrier at a temperature of 250 to 375 F. thus to drive off the dissolvingwater and crystallize the salt content. During this procedure, theresidual formaldehyde is volatilized and lost. A resulting salt cake isformed consisting substantially entirely of sodium salts oforthophosphoric acid and about 6% of moisture. This salt may be used insalting out another batch of the phenol-formaldehyde condensationproduct in the manner described above, or in one of the modifications ofsuch procedure as set forth in my said copending application.

An alternative step is to add sufiicient sodium hydroxide to the saltsolution just before evaporating it to convert all of the salt contentto trisodium phosphate as a useful by-product. The addition of causticsoda for this purpose raises the pH to about 12. Since heating at thispH over a long period of time leads to conversion of the formaldehyde torelatively non-volatile substance, the conversion may be avoided byevaporating the water substantially immediately after adding the causticsoda. Thus, the caustic soda may be added just before flashdrying thesolution on the heated drum. By this procedure the addition of causticsoda and the drying may be accomplished within about 20 minutes. By thisprompt drying after raising the pH above 9, the formaldehyde isvolatilized before such conversion may occur.

Where the presence of formaldehyde is not detrimental to use of the saltsolution, with or without the added caustic soda to form Na PO theevaporating to solid salt may be dispensed with, and such iscontemplated as falling within the scope of the invention as expressedin the appended claims.

I claim:

1. The method of treating a solution in water containing sodium salts oforthophosphoric acid and small dissolved quantities of phenol,formaldehyde, phenolformaldehyde, phenol-alcohols and a resin-formingcondensation product of phenol and formaldehyde, which comprises heatingthe solution having a pH from 5 to 9 at a temperature upwardly from 70C. whereby to effect formation of two liquid phases, separating andremoving from the lower aqueous phase the upper liquid phase resultinglycontaining phenol-formaldehyde resin, continuing the heating of theremaining aqueous phase and thereby forming a precipitate containingmaterial originating from phenolic constituents-of the originalsolution, and separating the precipitate from the remaining aqueous saltsolution containing dissolved formaldehyde.

2. The process of claim 1 followed by evaporating water from thesolution and forming a solid salt residue whereby the formaldehydecontent escapes with the water vapor.

3. The process of claim 1 followed by adding caustic soda to the saltsolution in quantity to form trisodium phosphate.

4. The process of claim 3 followed by evaporating water from thesolution and providing a solid salt residue.

5. The process of claim 4 wherein the evaporation is carried out byflash-drying water from the solution substantially immediately afteraddition of the caustic soda whereby formaldehyde escapes with watervapor.

6. The method of treating a solution in water containing sodium salts oforthophosphoric acid and small dissolved quantities of phenol,formaldehyde, phenol-alcohols and a resin-forming condensation productof phenol and formaldehyde, which comprises heating at atmosphericpressure said solution having a pH from 5 to 9 at a temperature upwardlyfrom 70 C. to its boiling point, whereby to effect formation of twoliquid phases, separating and removing from the lower aqueous phase theupper liquid phase resultingly containing phenolformaldehyde resin,continuing the heating of the remaining aqueous phase and therebyforming a precipitate containing material originating from phenolicconstituents of the original solution, and separating the precipitatefrom the remaining aqueous salt solution containing dissolvedformaldehyde.

7. The process of claim 6 followed by evaporating the solution andforming a solid salt residue whereby the formaldehyde content escapeswith the water vapor.

8. The process of claim 6 followed by adding caustic soda to the saltsolution in quantity to form trisodium phosphate.

9. The process of claim 8 followed by evaporating water from thesolution and providing a solid salt residue.

10. The process of claim 9 wherein the evaporation is carried out byflash-drying water from the solution substantially immediately afteraddition of the caustic soda whereby formaldehyde escapes with watervapor.

11. The method of treating a solution in water containing sodium saltsof orthophosphoric acid and small dissolved quantities of phenol,formaldehyde, phenolalcohols and a resin-forming condensation product ofphenol and formaldehyde, which comprises heating the solution having apH from 5 to 9 at a temperature up wardly from 70 C. whereby to effectformation of an aqueous phase and a resin-containing phase, continuingthe heating of the aqueous phase and thereby forming a precipitatecontaining material originating from phenolic constituents of theoriginal solution, and isolating the resulting aqueous phase as a saltsolution containing dissolved formaldehyde.

12. The process of claim 11 followed by evaporating water from thesolution and forming a solid salt residue whereby the formaldehydecontent escapes with the water vapor.

13. The process of claim 11 followed by adding caustic soda to the saltsolution in quantity to form trisodium phosphate.

14. The process of claim 13 followed by evaporating water from thesolution and providing a solid salt residue.

15. The process of claim 14 wherein the evaporation is carried out byflash-drying water from the solution substantially immediately afteraddition of the caustic soda whereby formaldehyde escapes with watervapor.

16. The method of treating a solution in water containing'sodium saltsof orthophosphoric acid and small dissolved quantities of phenol,formaldehyde, phenolalcohols and a resin-forming condensation product ofphenol and formaldehyde, which comprises heating at atmospheric pressuresaid solution having a pH from 5 to 9 at a temperature upwardly from 70C. to its boiling point, whereby to effect formation of an aqueous phaseand a resin-containing phase, continuing the heating of the aqueousphase and thereby forming a precipitate containing material originatingfrom phenolic constituents of the original solution, and isolating theresulting aqueous phase as a salt solution containing dissolvedformaldehyde.

17. The process of claim 16 followed by evaporating the solution andforming a solid salt residue whereby the formaldehyde content escapeswith the water vapor.

18. The process of claim 16 followed by adding caustic References Citedin the file of this patent UNITED STATES PATENTS Foulds et a1 Nov. 29,1949 Lee et al. Apr. 20, 1954

1. THE METHOD OF TREATING A SOLUTION IN WATER CONTAINING SODIUM SALTS OFORTHOPHOSPHORIC ACID AND SMALL DISSOLVED QUANTIUTIES OF PHENOL,FORMALDEHYDE, PHENOLFORMALDEHYDE, PHENOL-ALCOHOLS AND A RESIN-FORMINGCONDENSATION PRODUCT OF PHENOL AND FORMALDHEYDE, WHICH COMPRISES HEATINGTHE SOLUTION HAVING A PH FROM 5 TO 9 AT A TEMPERATURE UPWARDLY FROM70*C. WHEREBY TO EFFECT FORMATION OF TWO LIQUID PHASES, SEPARATING ANDREMOVING FROM THE LOWER AQUEOUS PHASE AND GHERESULTINGLY CONTAININGPHENOL-FORMALDEHYDE RESIN, CONTINUING THE HEATING OF THE REAMININGAQUEOUS PHASE AND THEREBY FORMING A PRECIPITATE FROM THE REMAININGAQUEOUS FROM PHENOLIC CONSTITUTNTS OF THE ORIGINAL SOLUTION, ANDSEPARATING THE PRECIPITATE FROM THE REMAINIG AQUEOUS SLAT SOLUTIONCONTAINING DISSOLVED FORMALDEHYDE.